Labeling machines are used to apply labels to all types of containers, both cylindrical containers and non-cylindrical containers, such as regular and irregular shaped polygons. One type of conventional label is a self-stick label, also called a pressure-sensitive label, which is carried by a backing strip. Self-stick labels are expensive and create a large amount of waste. Self-stick labels typically used with high-density polyethylene (HDPE) containers, such as milk jugs and juice bottles, are commonly a paper/propylene/adhesive laminate. When such self-stick labels are applied to conventional HDPE containers, the label must be cut out, often by hand, before the container can be recycled. Therefore, a tremendous amount of waste is created by the use of conventional laminated, self-stick labels on the estimated eight to ten billion one-gallon and half-gallon HDPE containers used in the U.S. annually.
Another type of commonly used labels is cut from continuous label material wound onto a roll. Labels made from continuous label material are more economical than self-stick labels and are often made from thin, stretchable film. To reduce the cost, the film keeps being made thinner. This stretchiness can make it difficult to ensure that the labels are properly cut.
Conventional labeling machines remove the continuous label material from the roll and feed the label material to a cutting system. The continuous label material is then cut into labels which are transferred face down onto the circumferential surface of a vacuum drum where they are held in place by vacuum. As the drum rotates the labels pass a glue roller which applies adhesive to the back (outer) surface of the label, typically at its leading and trailing edges. The label, with the adhesive applied thereto, is released from the drum as it comes into contact with and is applied to a container.